This is because the Mangler's ability applies in layer 7B, while the bonesplitter applies in 7C

Comments

• Calica

  2017-12-24 17:26:09

  Sup bitches, witches, Haters, and trolls.

  whats a layer
• Tatterhood

  2017-12-24 17:59:44

  Calica said:

  whats a layer

  It's one of the more technical aspects of the Magic rules, but here's the short(ish) version.
  
  Magic has various cards that create continuous effects, like "all creatures get +1/+1" or "creatures can't attack", or whatever. Sometimes, it matters what order you apply these effects in. If you have a card that turns all creatures red and another one that turns all creatures blue, which one "wins"? The usual answer is that the effects are applied in timestamp order, so the most recent one can override the other one.
  
  However if you just do everything in timestamp order, you get unintuitive things. If you play a card that says "red creatures can't attack" and then later "all creatures are red", you'd expect that to mean that nothing can attack, but if you strictly follow timestamps they aren't red "yet" when you decide whether they can attack. So basically the solution to this is that different types of continuous effects apply in different "layers", and lower numbered layers are applied first, then things are applied in timestamp order within a layer. In theory this system is designed so that it just works in the way people expect and you don't actually have to ever care about layers in order to play Magic, but once in a while it matters, eg. here.
  
• vtk

  2017-12-26 17:31:37

  embrace the confusion
  

  Are layers numbered sequentially, or by milepost?
• DYRE

  2017-12-31 02:41:28

  http://gatherer.wizards.com/Pages/Card/Details.aspx?name=Opalescence said:

  This is the current interaction between Humility and Opalescence: The type-changing effect applies at layer 4, but the rest happens in the applicable layers. The rest of it will apply even if the permanent loses its ability before it’s finished applying. So if Opalescence, Humility, and Worship are on the battlefield and Opalescence entered the battlefield before Humility, the following is true: Layer 4: Humility and Worship each become creatures that are still enchantments. (Opalescence). Layer 6: Humility and Worship each lose their abilities. (Humility) Layer 7b: Humility becomes 4/4 and Worship becomes 4/4. (Opalescence). Humility becomes 1/1 and Worship becomes 1/1 (Humility). But if Humility entered the battlefield before Opalescence, the following is true: Layer 4: Humility and Worship each become creatures that are still enchantments (Opalescence). Layer 6: Humility and Worship each lose their abilities (Humility). Layer 7b: Humility becomes 1/1 and Worship becomes 1/1 (Humility). Humility becomes 4/4 and Worship becomes 4/4 (Opalescence).